The process products find use, inter alia, as intermediates in the preparation of fuel additives (U.S. Pat. Nos. 3,275,554 A; DE 21 25 039 A and DE 36 11 230 A), surfactants, medicaments and crop protection compositions, hardeners for epoxy resins, catalysts for polyurethanes, intermediates for preparation of quaternary ammonium compounds, plasticizers, corrosion inhibitors, synthetic resins, ion exchangers, textile assistants, dyes, vulcanization accelerants and/or emulsifiers.
EP 963 975 A1 and EP 1 106 600 A2 (both BASF AG) describe processes for preparing amines from, respectively, alcohols and aldehydes or ketones, and nitrogen compounds, using a catalyst whose catalytically active material comprises 22-40% by weight (and 22-45% by weight) of oxygen compounds of zirconium, 1-30% by weight of oxygen compounds of copper and 15-50% by weight (and 5-50% by weight) each of oxygen compounds of nickel and of cobalt.
WO 03/076386 A and EP 1 431 271 A1 (both BASF AG) also teach catalysts of the abovementioned type for aminations. No Sn content is taught.
EP 514 692 A2 (BASF AG) relates to a process for preparing amines from alkanols in the presence of catalysts comprising Cu, Ni, optionally Co, ZrO2 and/or Al2O3.
The preferred catalyst consists of 55% by weight of Al2O3, 36% by weight of Cu and 7% by weight of Ni (example 1). No Sn content is taught.
WO 03/051508 A1 (Huntsman Petrochemical Corp.) relates to processes for aminating alcohols using specific Cu/Ni/Zr/Sn-containing catalysts which, in a further configuration, comprise Cr instead of Zr (see page 4 lines 10-16). The catalysts described in this WO application do not comprise any aluminum oxide or any cobalt.
WO 2007/036496 A (BASF AG) describes a process for preparing aminodiglycol (ADG) and morpholine by reacting diethylene glycol (DEG) with ammonia in the presence of a transition metal heterogeneous catalyst, wherein the catalytically active material of the catalyst, before the treatment with hydrogen, comprises oxygen compounds of aluminum and/or zirconium, of copper, of nickel and of cobalt, and the shaped catalyst body has specific dimensions. No Sn content is taught.
DE 28 44 984 A1 (Shell Int. Res.) describes processes for preparing an amine by reacting an alcohol, aldehyde or ketone having up to 25 carbon atoms with ammonia or a primary or secondary amine over a catalyst which comprises Cu, Sn and optionally alkali metal or alkaline earth metal on a porous support, for example aluminum oxide. These catalysts do not comprise any nickel or any cobalt.
EP 839 574 A2 and EP 839 575 A2 (both BASF AG) describe catalysts for aminating alcohols, which comprise Ni, Co, Cu, Ru on a porous metal oxide support, for example aluminum oxide, silicon dioxide, titanium dioxide, zirconium dioxide, inter alia. Sn is mentioned among numerous possible promoters. The catalyst activity and catalyst stability are in need of improvement.
U.S. Pat. No. 6,147,261 (Shell Oil Corp.) teaches nickel and/or cobalt catalysts for amination of particular hydroxyalkanals, which optionally comprise a support, for example aluminum oxide, magnesium oxide, silica, inter alia. Preferred catalysts are Raney cobalt and Raney nickel. The catalysts described do not comprise Sn.
U.S. Pat. No. 6,534,441 B1 (Union Carbide) describes catalysts for the reductive amination of lower aliphatic alkane derivatives, the active material of which is said to profit from a synergistic effect of Ni and Re. Such catalysts are based on an aluminosilicate support with 5-65% by weight of silica. The catalysts may also comprise a promoter from numerous groups of the Periodic Table, including group IVA (Sn), IB (Cu), VIII (Ni, Co).
WO 98/26868 A1 (Batelle Memorial Institute) describes catalysts for reactions in the aqueous phase based on Ni, which comprise a promoter from the group of Cu, Sn, Ag, Re, Ru, or a combination thereof. The promoter content is <5% by weight. The amination of alcohols/aldehydes/ketones is not described. Nor is an aluminum oxide support one of the supports described.
WO 2004/084887 A1 (DuPont) claims a process for preparing pyrrolidone derivatives from levulinic acid and aromatic amines (reductive amination). Numerous different catalysts comprising noble metals in particular on different supports, also including alumina, are used. Sn is not present.
DE 19 53 263 A (BASF AG) discloses catalysts comprising cobalt, nickel and copper on aluminum oxide with a metal content of 5 to 80% by weight, especially 10 to 30% by weight, based on the overall catalyst, where the catalysts comprise, calculated on the metal content, 70 to 95% by weight of a mixture of cobalt and nickel, and 5 to 30% by weight of copper. For example, the catalyst possesses the composition of 10% by weight of CoO, 10% by weight of NiO and 4% by weight of CuO on Al2O3. The catalyst does not comprise Sn, and the catalyst activity and catalyst stability are in need of improvement.
WO 2008/006750 A1 (BASF AG) relates to particular Pb-, Bi-, Sn-, Sb- and/or In-doped, zirconium dioxide-, copper-, nickel- and cobalt-containing catalysts, and to the use thereof in processes for preparing an amine by reacting a primary or secondary alcohol, aldehyde and/or ketone with hydrogen and ammonia or a primary or secondary amine. Aluminum oxide supports are not taught.
WO 2009/080507 A1 (BASF SE) relates to particular Sn- and Co-doped, zirconium dioxide-copper- and nickel-containing catalysts, and to the use thereof in processes for preparing an amine by reacting a primary or secondary alcohol, aldehyde and/or ketone with hydrogen and ammonia or a primary or secondary amine. Aluminum oxide supports are not taught.
WO 2009/080506 A1 (BASF SE) describes particular Pb-, Bi-, Sn-, Mo-, Sb- and/or P-doped, zirconium dioxide-, nickel- and iron-containing catalysts, and the use thereof in processes for preparing an amine by reacting a primary or secondary alcohol, aldehyde and/or ketone with hydrogen and ammonia or a primary or secondary amine. Aluminum oxide supports are not taught. The catalysts preferably do not comprise Cu or Co.
WO 2009/080508 A1 (BASF SE) teaches particular Pb-, Bi-, Sn- and/or Sb-doped, zirconium dioxide-, copper-, nickel-, cobalt- and iron-containing catalysts, and the use thereof in processes for preparing an amine by reacting a primary or secondary alcohol, aldehyde and/or ketone with hydrogen and ammonia or a primary or secondary amine. Aluminum oxide supports are not taught.
WO 2009/114438 A2 (Huntsman Petrochem. Corp.) relates to the amination of cyclohexanedimethanol in the presence of hydrogen and ZrO2-supported metal catalysts, e.g. ZrO2/Cu/Ni/Sn.
A parallel European patent application with the same filing date (BASF SE) relates to particular doped aluminum oxide-, copper-, nickel-, cobalt- and tin-containing catalysts, and to the use thereof in processes for preparing an amine from a primary or secondary alcohol, aldehyde and/or ketone.
In the case of use of the very active prior art catalysts, including in particular the catalysts according to EP 963 975 A1 and EP 1 106 600 A2 (see above), there may be an increased extent of decarbonylation of the carbonyl function (which may have formed as an intermediate) in the reactants (alcohols, aldehydes, ketones) at elevated temperature. As a result of the large amount of heat of hydrogenation released, the formation of methane by hydrogenation of carbon monoxide (CO) leads to a ‘runaway risk’, i.e. an uncontrolled temperature rise in the reactor. When CO is scavenged by amines, secondary components containing methyl groups are formed.
Furthermore, in the case of use of the very active prior art amination catalysts, in particular of those based on zirconium dioxide, there may be undesired ether cleavage, which necessitates improvement in the yield of products of economic interest, for example ADG and morpholine (MOR).
In the course of amination of diethylene glycol (DEG), there is, for example, an increased extent of formation of undesired methoxyethanol or methoxyethylamine. Methoxyethanol is toxic, can be removed from morpholine only with difficulty owing to its physical properties, and can thus lead to problems with regard to specification and product quality.
In the example of the amination of diethylene glycol (DEG), “decarbonylation” is considered more particularly to be the sum of undesired components (methanol, methoxyethanol, methoxyethylamine, N-methylmorpholine and methoxyethylmorpholine), which form from DEG via methoxyethanol according to the reaction scheme:

The reaction mechanism of the amination of primary or secondary alcohols is assumed to be that the alcohol is first dehydrogenated over a metal site to the corresponding aldehyde. In this context, the copper or else nickel is probably of particular significance as a dehydrogenating component. When aldehydes are used for the amination, this step is absent.
The aldehyde formed or used can be aminated by reaction with ammonia or primary or secondary amine with elimination of water and subsequent hydrogenation. This condensation of the aldehyde with the abovementioned nitrogen compound is probably catalyzed by acidic sites of the catalyst. However, the aldehyde can also be decarbonylated in an undesired side reaction, which means that the aldehyde function is eliminated as CO. The decarbonylation or methanization probably takes place over a metal site. The CO is hydrogenated to methane over the hydrogenation catalyst, and so the methane formation indicates the extent of decarbonylation. The decarbonylation forms the abovementioned undesired by-products, for example methoxyethanol and/or methoxyethylamine in the abovementioned case.
The desired condensation of the aldehyde with ammonia or primary or secondary amine and the undesired decarbonylation of the aldehyde are parallel reactions, of which the desired condensation is probably acid-catalyzed, whereas the undesired decarbonylation is catalyzed by metallic sites.